How to play a sound after script finishes?
You could play a MP3 file using the aud module

import aud
import time

sound = aud.Factory.file(pathToMP3 )
device = aud.device()
handle = device.play(sound)
# omit this to play full sound file
time.sleep(5) 
handle.stop()


Alternatively you could launch any external application as described here: Run an external application with the bge